Paper feeding cassette

ABSTRACT

A paper feeding cassette includes a cassette body detachably mounted to an image forming apparatus, and an alignment unit disposed on an inner surface of the cassette body to pressurize a plurality of stacked sheets of recording medium from one side thereof when the cassette body is mounted in the image forming apparatus. Accordingly, the sheets of recording medium can be more accurately picked up and a stable image quality can be obtained.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 119 (a) of KoreanPatent Application No. 2005-113568 filed on Nov. 25, 2005, the entirecontent of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present general inventive concept relates to a paper feeding deviceto feed a printing medium into an image forming apparatus. Moreparticularly, the present general inventive concept relates to a paperfeeding cassette of a paper feeding device.

2. Description of the Related Art

An image forming apparatus, such as a copier, a printer and a facsimile,for forming a certain image on a printing medium may typically beclassified as an electrophotographic type that uses a photosensitivebody, an inkjet type that directly ejects a developer onto the printingmedium, a thermal transfer type, a bubble jet type, a dye sublimationtype, a dot matrix type, etc.

Since digital cameras have recently gained widespread popularity, anincreased number of users desire to directly output an imagephotographed by a digital camera onto the printing medium as well asstore the image in a storage medium such as a hard disk drive. To thisend, a photo printer has been developed. The photo printer is a printerthat is dedicated to printing digital photos from images stored in thedigital camera connected by a PictBridge, or that prints images storedin a memory card. The photo printer may be classified as the bubble jettype, the thermal transfer type, and the dye sublimation type.

The photo printer is designed to have a compact size so that it isportable and easy to carry and a photographed image can be directlyprinted at an outdoor place. The printing medium includes a specialpaper dedicated to printing a photo (i.e., photo paper), and the size ofthe photo paper is typically either 4×6 inches or A4 size.

The image forming apparatus has a paper feeding device which supplies aprinting medium such as a paper into the image forming apparatus. Thepaper feeding device includes a paper feeding cassette having aplurality of printing medium (i.e., sheets) stacked therein and apick-up unit to pick up the printing medium sheet by sheet from thepaper feeding cassette to feed the printing medium into a printing partof the image forming apparatus.

The paper feeding cassette is detachably mounted to the image formingapparatus such that the plurality of sheets of printing medium can beeasily stacked in the paper feeding cassette.

When stacked in the paper feeding cassette, the plurality of sheets ofprinting medium should be accurately aligned therein. If the printingmedium stacked in the paper feeding cassette is not accurately aligned,various errors occur when the image forming apparatus performs printingor the printing medium is fed. These errors result in a paper jam or acurl of the printing medium.

Accordingly, it is very important to align the printing medium stackedin the paper feeding cassette in order to increase the operability anddurability of the image forming apparatus.

The alignment of the printing medium in the paper feeding cassette isespecially important for an image forming apparatus such as the photoprinter which uses a high-priced paper dedicated to printing photos(e.g., the photo paper), or an image forming apparatus from which apaper feeding cassette can be separated such that the image formingapparatus has a compact size.

SUMMARY OF THE INVENTION

Accordingly, the present general inventive concept provides a paperfeeding cassette which can perform an accurate picking-up operation sothat a stable image quality can be obtained.

The present general inventive concept also provides a paper feedingcassette which can easily and accurately align sheets of a printingmedium.

The present general inventive concept also provides a paper feedingcassette to prevent sheets of a printing medium from overlapping whenbeing picked up, not by an individual sheet such that the printingmedium can be properly picked up from a paper feeding cassette.

Additional aspects of the present general inventive concept will be setforth in part in the description which follows and, in part, will beobvious from the description, or may be learned by practice of thegeneral inventive concept.

The foregoing and/or other aspects of the present general inventiveconcept are achieved by providing a paper feeding cassette including acassette body detachably mounted to an image forming apparatus, and analignment unit disposed on an inner surface of the cassette body topressurize a plurality of stacked sheets of recording medium from oneside thereof when the cassette body is mounted in the image formingapparatus.

The alignment unit may include at least one biasing member to be biasedtoward an inner space of the cassette body when the cassette body ismounted in the image forming apparatus.

The alignment unit may include a guide member to guide the biasing ofthe biasing member, and the guide member and the biasing member may bealigned to be movable relative to each other.

The biasing member may be formed at an inner surface of the cassettebody to form a guide recess between the inner surface of the cassettebody and the biasing member to receive the guide member therein. Thebiasing member may be formed of an elastic body having a first end fixedon the inner surface of the cassette body and a second end which iselastically biased toward the inner space of the cassette body, and theguide recess to receive the guide member is formed between the first andsecond ends of the biasing member.

The cassette body may have a reference surface at a first inner surfaceand an alignment unit at a second surface opposite to the referencesurface.

The reference surface may have a plurality of contacting surfacesprotruding toward an inner space of the cassette body by the samelengths.

The paper feeding cassette may further include a cover slidinglydisposed at a top portion of the cassette body.

The guide member may be fixedly connected to the cover.

The cover and the cassette body may include a guide protrusion and aguide groove at a contacting portion therebetween.

The cover may further include an elastic rib to elastically pressurize atop side of the sheets of recording medium stacked in the cassette body.

The cassette body may further include a protrusion portion at the topportion to incline the cover at a slight angle when the cassette body ismounted in the image forming apparatus.

The foregoing and/or other aspects of the present general inventiveconcept are achieved by providing a paper feeding cassette usable in animage forming apparatus, the cassette including a cassette body toaccommodate recording media and being mountable in a mounting part ofthe image forming apparatus, and an alignment unit disposed on a side ofthe cassette body to push the recording media against a referencesurface in the cassette body as the cassette body is being mounted inthe mounting part.

The foregoing and/or other aspects of the present general inventiveconcept are achieved by providing a paper feeding cassette usable in animage forming apparatus, the cassette including a body having top andbottom portions slideably coupled to one another to accommodate sheetsof recording media therebetween, and an alignment unit havingcomplementary projecting parts disposed on the top and bottom portionsof the body such that the complementary projecting parts engage eachother as the top and bottom portions are moved with respect to eachother into a mounting position such that the engagement of thecomplementary projecting parts pushes the recording media into analigned position.

The foregoing and/or other aspects of the present general inventiveconcept are achieved by providing a paper feed cassette, including atray part to accommodate sheets of printing media and having a biasingmember extending along an inner sidewall thereof, and a cover partcoupled to the tray part and having a guide member extending from a sidebottom portion thereof such that the biasing member engages the guidemember when the cover part is moved with respect to the tray part into amounting position.

The foregoing and/or other aspects of the present general inventiveconcept are achieved by providing a paper cassette mountable in an imageforming apparatus, the cassette including a bottom part to accommodateprinting media, and a top part movably coupled to the bottom partbetween a first position with respect to the bottom part when thecassette is dismounted from the image forming apparatus, and a secondposition with respect to the bottom part when the cassette is mounted inthe image forming apparatus.

The foregoing and/or other aspects of the present general inventiveconcept are achieved by providing an image forming apparatus including apaper feeding cassette having a body with top and bottom portionsslideably coupled to one another to accommodate sheets of recordingmedia therebetween, and an alignment unit having complementaryprojecting parts disposed on the top and bottom portions of the bodysuch that the complementary projecting parts engage each other as thetop and bottom portions are moved with respect to each other into amounting position such that the engagement of the complementaryprojecting parts pushes the recording media into an aligned position.The image forming apparatus further includes a mounting part having areceiving space to receive the paper feeding cassette into the mountingposition.

The foregoing and/or other aspects of the present general inventiveconcept are achieved by providing an image forming apparatus, includinga mounting part and a paper cassette mountable in the mounting part. Thecassette includes a body to accommodate recording media therein, and acover slidably coupled to the body to cover the recording media and toslide from a first end of the body to a second end of the body as thecassette is inserted in the mounting part.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the present general inventive concept willbecome apparent and more readily appreciated from the followingdescription of the embodiments, taken in conjunction with theaccompanying drawings of which:

FIG. 1 is a perspective view illustrating a paper feeding cassette in astate in which the paper feeding cassette is not mounted in an imageforming apparatus, according to an embodiment of the present generalinventive concept;

FIG. 2 is a perspective view illustrating the paper feeding cassette ofFIG. 1 in a state in which the paper feeding cassette is mounted in animage forming apparatus, according to an embodiment of the presentgeneral inventive concept;

FIG. 3A is a transverse cross-sectional view illustrating the paperfeeding cassette of FIG. 1 in the state in which the paper feedingcassette is not mounted in the image forming apparatus, according to anembodiment of the present general inventive concept;

FIG. 3B is an enlarged view illustrating an alignment unit of the paperfeeding cassette of FIG. 3A at reference point IIIA;

FIG. 4A is a transverse cross-sectional view illustrating the paperfeeding cassette of FIG. 1 in the state in which the paper feedingcassette is mounted in the image forming apparatus, according to anembodiment of the present general inventive concept;

FIG. 4B is an enlarged view illustrating the alignment unit of the paperfeeding cassette of FIG. 4A at reference point IVA;

FIG. 5 is a sectional side view illustrating the paper feeding cassetteof FIG. 1 along reference line V-V;

FIG. 6 is a sectional side view illustrating the paper feeding cassetteof FIG. 2 along reference line VI-VI; and

FIG. 7 is a perspective view illustrating a paper feeding cassetteaccording to another embodiment of the present general inventiveconcept.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentgeneral inventive concept, examples of which are illustrated in theaccompanying drawings, wherein like reference numerals refer to the likeelements throughout. The embodiments are described below in order toexplain the present general inventive concept by referring to thefigures.

FIGS. 1 through 6 are views illustrating a paper feeding cassetteaccording to an embodiment of the present general inventive concept.

As illustrated in FIGS. 1 to 6, the paper feeding cassette includes acassette body 10, which has an inner space in which to stack a pluralityof sheets of recording medium P. The cassette body 10 is detachablymounted in an image forming apparatus 100.

Referring to FIGS. 3A and 4A, a plurality of contacting surfaces 11protrude toward the inner space of the cassette body 10 at one sidethereof (e.g., the left side of FIGS. 3A and 5). The contacting surfaces11 have protruding lengths that are the same.

The plurality of contacting surfaces 11 protrude such that a frictionforce that occurs when the recording medium P contacts an entire side ofthe cassette body 10 can be decreased. In other words, the contactingsurfaces 11 decrease an area of contact between the side of the cassettebody 10 and the recording medium P. Therefore, a pick-up roller 55 (seeFIGS. 4A and 6) can more easily pick up the recording medium P.

An inside of the plurality of contacting surfaces 11 serves as areference surface when the sheets of the recording medium P are aligned.

An alignment unit 20 is disposed at an opposite surface (i.e., the rightside of FIGS. 3 and 5) to the reference surface of the cassette body 10to align the stacked sheets of recording medium P.

The alignment unit 20 includes a biasing member 22 and a guide member21. The biasing member 22 is biased toward the inner space of thecassette body 10 as the cassette body 10 is mounted to a mount part 110of the image forming apparatus 100, and the guide member 21 guides thebiasing of the biasing member 22.

As the biasing member 22 is biased toward the inner space of thecassette body 10 by the guide member 21, the biasing member 22 pressesone side of the recording medium P stacked in the cassette body 10 toalign the widths of the sheets of the recording medium P against thereference surface defined by the contacting surfaces 11.

The guide member 21 is aligned in a line with the biasing member 22 andis connected to the image forming apparatus 100 or a cover 30 of thepaper feeding cassette.

The biasing member 22 and the guide member 21 are formed to be movablerelative to each other. In other words, if the guide member 21 is fixed,the biasing member 22 is movable toward the guide member 21, and if thebiasing member 22 is fixed, the guide member 21 is movable toward thebiasing member 22.

The biasing member 22 may be formed of an elastic body having a firstend 22 a fixed to the inside of the cassette body 10 and a second end 22b which is elastically biased toward the inner space of the cassettebody 10. A guide recess 22 c is formed between the first end 22 a andthe second end 22 b to receive and guide a leading end of the guidemember 21.

A penetrating hole 18 of a predetermined size may be formed at a bottomsurface of the cassette body 10 such that the recording medium P can beseparated. For example, a user may insert and object or finger throughthe penetrating hole 18 to separate the sheets of recording medium P,which are stacked in the cassette body 10.

The cover 30 is formed on a top surface of the cassette body 10 toprevent foreign material from outside the cassette body 10 from enteringthe cassette body 10, and the cover 30 and the cassette body 10 areslidingly formed with respect to each other. Referring to FIGS. 1 and 2,the cover 30 may have an area to partially cover the top surface of thecassette body 10. However, it should be understood that other types ofcovers may alternatively be used, and the cover 30 illustrated in FIGS.1 to 3A and 4A to 6 is not intended to limit the scope of the presentgeneral inventive concept. For example, the cover 30 may have an areathat fully covers the top surface of the cassette body 10.

Referring to FIGS. 3A and 4A, the sliding structure of the cover 30 andthe cassette body 10 can be implemented using a guide protrusion 35 anda guide groove 15 which are formed at a contacting portion between thecover 30 and the cassette body 10 to correspond to each other.

In the present embodiment, the guide member 21 can be fixedly connectedto a bottom surface of the cover 30. Accordingly, the guide member 21and the cover 30 move together in the same direction with each other.Since the cover 30 and the cassette body 10 slidingly engage with eachother, the guide member 21 fixed on the cover 30 and the biasing member22 fixed on the cassette body 10 also slidingly engage with each other.For example, the guide member 21 on the cover 30 may engage the biasingmember 22 on the cassette body 10, as the cassette body 10 is mounted inthe mount part 110 of the image forming apparatus 100.

Referring to FIGS. 5 and 6, an elastic rib 31 is formed at one side ofthe bottom surface of the cover 30 to be downwardly biased. A leadingend portion of the elastic rib 31 presses an upper most sheet of therecording medium P stacked in the cassette body 10 to flatten therecording medium P.

FIG. 7 is a perspective view illustrating the paper feeding cassetteaccording to another embodiment of the present general inventiveconcept. As illustrated in FIG. 7, the cover 30 may further include apivot cover 40, which is pivotably coupled to a front side of the cover30. Therefore, the sheets of the recording medium P can be more easilystacked into the cassette body 10 and foreign material from outside intothe cassette body 10 can be more effectively prevented from entering thecassette body 10.

Referring back to FIGS. 5 and 6, the cassette body 10 has protrusionportions 14, which are curved with a predetermined radius, on topsurfaces of opposite left and right sidewalls. When the cover 30 slidestoward a front of the cassette body 10, the cover 30 contacts theprotrusion portions 14 to incline to a slight angle, and accordingly apressurizing force of the elastic rib 31 is increased by the inclinedangle.

Referring to FIG. 3A, the mount part 110 of the image forming apparatus100 into which the paper feeding cassette of the present embodiment isdetachably mounted includes a receiving recess 111 to receive the cover30 and a receiving space 112 to receive a rear side of the cassette body10.

A plurality of dams 113 are disposed at a rear side of the receivingspace 112 to respectively sit in a plurality of penetrating openings 16formed at the rear side of the cassette body 10. Here, the dams 113 havegeneral structures to prevent a feeding of overlapping sheets of therecording medium P, while the plurality of stacked sheets of recordingmedium P in the cassette body 10 are picked up by the pick-up roller 55(see FIGS. 4A and 6).

Referring to FIGS. 3A and 4A, hook devices 114 are symmetrically andmovably disposed at opposite sides of the receiving space 112. The hookdevices 114 are disposed at the rear side of the receiving space 112 toengage a plurality of protrusions 17 disposed on the right and left rearsides of the cassette body 10.

The operation of the paper feeding cassette according to the embodimentsof the present general inventive concept will now be explained withreference to FIGS. 1 to 6. However, it should be understood that thisdescription can also be applied to the embodiment of FIG. 7.

The plurality of sheets of recording medium P are stacked in thecassette body 10 to contact the plurality of contacting surfaces 11formed at one inner side of the cassette body 10 to form the referencesurface.

The cassette body 10 and the cover 30 are then inserted into the mountpart 110 of the image forming apparatus 100.

As the paper feeding cassette is inserted into the mount part 110, thecover 30 is held by the receiving recess 111 to prevent the cover 30from being inserted further into the receiving space 112 such that thecassette body 10 is slid with respect to the cover 30 to the rear sideof the receiving space 112.

As the cassette body 10 is inserted in the mount part 110 toward therear side of the receiving space 112, the protrusions 17 on the cassettebody 10 move toward the hook devices 114 such that each protrusion 17engages each hook device 114 and the cassette body 10 is fixedly mountedto the image forming apparatus 100.

As described above, since the cassette body 10 and the cover 30 are slidrelative to each other, the guide member 21 fixedly connected to thecover 30 is inserted into the guide recess 22 c (see FIGS. 3B and 4B) ofthe biasing member 22 disposed at the inside of the cassette body 10.Accordingly, the second end 22 b of the biasing member 22 is elasticallybiased to press one side of the stacked sheets of recording media P sothat widths of the sheets of recording medium P can be aligned againstthe reference surface.

In other words, according to the present embodiment, the stacked sheetsof recording medium P can be automatically aligned simultaneously with amounting of the paper feeding cassette to the image forming apparatus100.

Therefore, the alignment operation is very easily performed to provideconvenience to users of the image forming apparatus 100. Additionally,the sheets of recording medium P are accurately aligned so that thealigned sheets of recording medium P can be accurately and minutelysupplied to an image forming part of the image forming apparatus 100.Therefore, a printing quality can be enhanced.

If the paper feeding cassette has a structure in which the recordingmedium P are pressurized from only one side in the cassette body 10, thepressurizing force for aligning the sheets of recording medium P is nottoo excessive so as to cause overlapped sheets of the recording medium Pto be picked up by the pick up roller 55.

According to the various embodiments of the present general inventiveconcept, sheets of recording medium can be more accurately picked up anda stable image quality can be obtained.

According to the various embodiments of the present general inventiveconcept, sheets of a recording medium can be easily and accuratelyaligned.

Additionally, according to the embodiments of the present generalinventive concept, sheets of a recording medium are prevented fromoverlapping when being picked. Additionally, individual sheets areproperly picked up from the paper feeding cassette.

Although a few embodiments of the present general inventive concept havebeen shown and described, it will be appreciated by those skilled in theart that changes may be made in these embodiments without departing fromthe principles and spirit of the general inventive concept, the scope ofwhich is defined in the appended claims and their equivalents.

1. A paper feeding cassette, comprising: a cassette body detachablymounted to an image forming apparatus; and an alignment unit disposed onan inner surface of the cassette body to pressurize a plurality ofsheets of recording medium from one side thereof when the cassette bodyis mounted in the image forming apparatus.
 2. The paper feeding cassetteas claimed in claim 1, wherein the alignment unit comprises at least onebiasing member to be biased toward an inner space of the cassette bodyas the cassette body is mounted in the image forming apparatus.
 3. Thepaper feeding cassette as claimed in claim 2, wherein the alignment unitcomprises a guide member to guide the biasing of the biasing member, andthe guide member and the biasing member are aligned to be movablerelative to each other.
 4. The paper feeding cassette as claimed inclaim 3, wherein the biasing member is formed at an inner surface of thecassette body to form a guide recess between the inner surface of thecassette body and the biasing member to receive the guide membertherein.
 5. The paper feeding cassette as claimed in claim 4, whereinthe biasing member is formed of an elastic body having a first end fixedon the inner surface of the cassette body and a second end which iselastically biased toward the inner space of the cassette body, and theguide recess to receive the guide member is formed between the first andsecond ends of the biasing member.
 6. The paper feeding cassette asclaimed in claim 3, further comprising: a cover slidingly disposed at atop portion of the cassette body.
 7. The paper feeding cassette asclaimed in claim 6, wherein the guide member is fixedly connected to thecover.
 8. The paper feeding cassette as claimed in claim 7, wherein thecover and the cassette body comprise a guide protrusion and a guidegroove at a contacting portion therebetween.
 9. The paper feedingcassette as claimed in claim 8, wherein the cover further comprises anelastic rib to elastically pressurize a top side of the sheets of therecording medium stacked in the cassette body.
 10. The paper feedingcassette as claimed in claim 9, wherein the cassette body furthercomprises a protrusion portion at a top portion thereof to incline thecover at a slight angle when the cassette body is mounted in the imageforming apparatus.
 11. The paper feeding cassette as claimed in claim 1,wherein the cassette body has a reference surface at a first innersurface and the alignment unit at a second inner surface opposite to thereference surface.
 12. The paper feeding cassette as claimed in claim11, wherein the reference surface has a plurality of contacting surfacesprotruding into an inner space of the cassette body by same lengths. 13.A paper feeding cassette usable in an image forming apparatus, thecassette comprising: a cassette body to accommodate recording media andbeing mountable in a mounting part of the image forming apparatus; andan alignment unit disposed on a side of the cassette body to push therecording media against a reference surface in the cassette body as thecassette body is being mounted in the mounting part.
 14. The cassette asclaimed in claim 13, wherein the alignment unit is disposed on a firstinner side of the cassette body and the reference surface is disposed ata second inner side opposite to the first inner side.
 15. The cassetteas claimed in claim 13, further comprising: a cover slidably engagedwith the cassette body to cover a top surface of the cassette body. 16.The cassette as claimed in claim 15, wherein the alignment unitcomprises: a biasing member extending from the side of the cassettebody; and a guide member extending from the cover to engage the biasingmember as the cover slides over the top surface of the cassette body.17. The cassette as claimed in claim 16, wherein the guide member pushesthe biasing member to extend further from the side into an inner spaceof the cassette body such that the biasing member contacts a side edgeof the recording media.
 18. The cassette as claimed in claim 16, whereinthe cover is disposed at a first end of the cassette body and slidesover the top surface of the cassette body toward a second end thereof asthe cassette body is mounted in the mounting part.
 19. The cassette asclaimed in claim 16, wherein the cover is coupled to outer sides of thecassette body, and as the cassette body is being mounted in the mountingpart, an outer portion of the cover engages an inner portion of themounting part such that the cover is prevented from moving furthertherein, while the cassette body is moved further into the mountingpart.
 20. The cassette as claimed in claim 15, wherein the cassette bodycomprises at least one protrusion portion extending upward from at leastone side wall on the top surface thereof to engage the cover as thecover slides over the top surface such that the cover is maintained at apredetermined non-horizontal angle when the cassette body is mounted inthe image forming apparatus.
 21. The cassette as claimed in claim 15,wherein the cover comprises: a parallel portion arranged to be parallelto the top surface of the cassette body and being slidable with respectthereto; and a pivotable portion coupled to the parallel portion andpivotable about an axis with respect thereto.
 22. The cassette asclaimed in claim 15, wherein the alignment unit comprises: a biasingmember extending from the side of the cassette body; and a guide memberextending from the cover to engage the biasing member as the cover andthe cassette body are moved relative to one another.
 23. The cassette asclaimed in claim 15, wherein the cover comprises an elastic ribextending from a bottom side thereof to apply a downward force on anuppermost sheet of recording media disposed in the cassette body.
 24. Apaper feeding cassette usable in an image forming apparatus, thecassette comprising: a body having top and bottom portions slideablycoupled to one another to accommodate sheets of recording mediatherebetween; and an alignment unit having complementary projectingparts disposed on the top and bottom portions of the body such that thecomplementary projecting parts engage each other as the top and bottomportions are moved with respect to each other into a mounting positionsuch that the engagement of the complementary projecting parts pushesthe recording media into an aligned position.
 25. The cassette asclaimed in claim 24, wherein the complementary projecting partscomprise: an elastic biasing member extending along an inner surface ofthe bottom portion of the body and forming a guide recess with the innersurface of the body; and a guide member extending along an inner surfaceof the top portion of the body to be received in the guide recess topush the elastic biasing member inward in the body.
 26. The cassette asclaimed in claim 24, wherein the top portion comprises a rib extendingfrom a bottom surface thereof to apply a force to an uppermost sheet ofthe recording media.
 27. A paper feed cassette, comprising: a tray partto accommodate sheets of printing media and having a biasing memberextending along an inner sidewall thereof; and a cover part coupled tothe tray part and having a guide member extending from a side bottomportion thereof such that the biasing member engages the guide memberwhen the cover part is moved with respect to the tray part into amounting position.
 28. The cassette as claimed in claim 27, wherein thebiasing member and guide member push the sheets of printing mediaagainst a reference surface in the tray part as the biasing and guidemembers engage each other.
 29. A paper cassette mountable in an imageforming apparatus, the cassette comprising: a bottom part to accommodateprinting media; and a top part movably coupled to the bottom partbetween a first position with respect to the bottom part when thecassette is dismounted from the image forming apparatus, and a secondposition with respect to the bottom part when the cassette is mounted inthe image forming apparatus.
 30. The cassette as claimed in claim 29,wherein the top part engages the image forming apparatus when thecassette is mounted such that the top part is moved from the firstposition to the second position as the cassette is mounted in the imageforming apparatus.
 31. The cassette as claimed in claim 29, furthercomprising: an alignment unit disposed between the top and bottom partsoperable by relative movement between the top and bottom parts to pushthe printing media into an aligned position as the top part is moved tothe second position.
 32. An image forming apparatus, comprising: a paperfeeding cassette including a body having top and bottom portionsslideably coupled to one another to accommodate sheets of recordingmedia therebetween, and an alignment unit having complementaryprojecting parts disposed on the top and bottom portions of the bodysuch that the complementary projecting parts engage each other as thetop and bottom portions are moved with respect to each other into amounting position such that the engagement of the complementaryprojecting parts pushes the recording media into an aligned position;and a mounting part having a receiving space to receive the paperfeeding cassette into the mounting position.
 33. The apparatus asclaimed in claim 32, further comprising: a pick up unit installedadjacent to the receiving space to pick up the recording media from thebody sheet by sheet.
 34. The apparatus as claimed in claim 32, whereinthe mounting part comprises a receiving recess to stop the top portionof the body from moving as the body is slidably inserted into thereceiving space while the bottom portion continues to slide toward arear side of the receiving space.
 35. The apparatus as claimed in claim34, wherein the top and bottom portions slide with respect to each otheras the body is slidably inserted in the receiving space such that thecomplementary projecting parts engage each other as the body is movedinto the receiving space.
 36. The apparatus as claimed in claim 32,wherein: an inner portion of the mounting part includes one or more hookparts, and a leading end of the bottom portion includes one or moreprotrusions extending laterally therefrom to engage the one or more hookparts to be stably mounted in the receiving space.
 37. The apparatus asclaimed in claim 32, wherein as a leading end of the cassette isinserted into the receiving space the top portion is slid with respectto the bottom portion away from the leading end toward a trailing end ofthe cassette.
 38. An image forming apparatus, comprising: a mountingpart; and a paper cassette mountable in the mounting part, the cassetteincluding a body to accommodate recording media therein, and a coverslidably coupled to the body to cover the recording media and to slidefrom a first end of the body to a second end of the body as the cassetteis inserted in the mounting part.